Copending, commonly assigned U.S. application Ser. No. 282,787 of July 13, 1981 and its equivalent Federal Republic of Germany application No. P 30 26 605.8 describe an acidproof, hydrolytically stable, optical and ophthalmic glass of low density wherein the sum total of vitrifying agents SiO.sub.2 +B.sub.2 O.sub.3 +Al.sub.2 O.sub.3 +GeO.sub.2 is 25-39% by weight. It can also comprise P.sub.2 O.sub.5 instead of GeO.sub.2. However, it is desired that this glass be improved for certain applications.